Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UMLS:C0029089 (ophthalmoplegia)
 3,338 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Large-scale deletions of human mitochondrial DNA (mtDNA) have been described in a clinical subgroup of mitochondrial encephalomyopathies associated with progressive external ophthalmoplegia and ragged-red fibers in skeletal muscle, including cases of Kearns-Sayre syndrome (KSS). Since the decrease in the activities of mtDNA-encoded respiratory-chain enzymes did not seem to be correlated to the sites of the deletions, the role played by the mtDNA deletions in the pathogenesis of these disorders has been unclear. To address this issue, we studied transcription and translation of deleted mtDNA in two patients with KSS harboring two different deletions. We found that the deleted genomes were transcriptionally active in both cases. Analysis of translation in one of the patients showed that the "fusion" mRNA derived from the region spanning the deletion did not seem to be translated. Thus, the biochemical defects in KSS can be explained by a lack of translation of mtDNA-encoded respiratory-chain polypeptides in some mitochondria, which, in turn, is probably due to the lack of indispensable mtDNA-encoded tRNAs in these organelles. These results imply that deleted mtDNAs may be segregated from normal genomes in this group of diseases. It seems likely that the absence of translation in proliferating mitochondria containing partially deleted genomes plays a major role in the pathogenesis of these disorders.
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PMID:Transcription and translation of deleted mitochondrial genomes in Kearns-Sayre syndrome: implications for pathogenesis. 168 52

Refsum's disease is a polyneuropathy due to a hereditary error in the metabolism of a fatty acid, phytanic acid, usually leading to cardiac failure only at an advanced stage of the disease. The authors report the case of two brothers with Refsum's disease revealed by a heart failure before the clinical stage of the peripheral neuropathy. In the younger brother, the affection started at the age of 22 years by an acute pulmonary oedema which revealed a dilated, hypokinetic myocardiopathy, associated with retinitis pigmentosa, ptosis, anosmia and biological myolysis. The normal plasma concentration of phytanic acid measured several times led to the conclusion of Kearns-Sayre syndrome even if certain aspects were atypical (moderate conduction disorders, no characteristic aspect in the muscle biopsy). Five years later, the older brother, aged 28, presents a dyspnea on effort which leads to the discovery of a hypokinetic, hypertrophic myocardiopathy, slightly dilated, associated with cardiac conduction disorders, retinitis pigmentosa, anosmia and biological myolysis. The plasma concentration of phytanic acid being very high. Refsum's disease was diagnosed and the diagnosis of younger brother was corrected. From the study of these two cases, the characteristics of the cardiac disorders can be specified: the cardiopathy can reveal the disease and correspond to a dilated or hypertrophic myocardiopathy. The diagnosis of the disease can be difficult because the plasma phytanic acid may remain at normal level, thus requiring the assay of the activity of phytanate oxydase. The existence of ophthalmologic signs (retinitis pigmentosa or progressive ophthalmoplegia externa) associated with a myocardiopathy must systematically lead to a search for Refsum's disease, this diagnosis having fundamental therapeutic implications (died, even plasmapheresis).(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:[Refsum's disease. Apropos of 2 cases disclosed by myocardiopathy]. 169 53

We reported a case of Kearns-Sayre syndrome with impaired respiratory regulation. A 55-year-old male was admitted to our hospital complaining of chronic progressive external ophthalmoplegia, limb muscle weakness and dyspnea. On admission, because arterial blood gas analysis showed marked alveolar hypoventilation, ventilatory response was measured and diminished chemosensitivity to both hypoxia and hypercapnia was found. His vital capacity and forced expiratory volume in 1 second were slightly decreased, and a chest X-ray film revealed a moderate degree of elevation of the bilateral diaphragm. Therefore, we considered that the diminished response to hypoxia and hypercapnia in this case was caused by an impairment of the respiratory center, as well as chemoreceptors and also the presence of respiratory muscular weakness.
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PMID:[A case of Kearns-Sayre syndrome with impaired respiratory regulation]. 175 13

Coenzyme Q10 (CoQ) content was measured in isolated muscle mitochondria from 25 patients with mitochondrial encephalomyopathies (MEM), most of whom had mitochondrial DNA mutations. The CoQ level was significantly lower in MEM patients than in controls. CoQ levels varied widely from patient to patient, especially in those with chronic progressive external ophthalmoplegia including Kearns-Sayre syndrome, which may explain, at least in part, the variable response of patients to CoQ administration.
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PMID:Muscle coenzyme Q10 in mitochondrial encephalomyopathies. 182 56

Genetic, biochemical and morphological investigations were conducted on skeletal muscle mitochondria from 6 cases of ocular myopathy: 4 cases with Kearns-Sayre syndrome (KSS) and 2 with chronic progressive external ophthalmoplegia. All of these 6 cases showed mitochondrial DNA (mtDNA) deletions in addition to normal sized DNA in the quadriceps muscle. The deletions ranging from 3 to 8 kbp were also mapped between nucleotides 5500 and 16000 by Southern blot. The deleted genes encoded for some subunits of complexes I, IV, V and 5-10 tRNAS. The boundaries of the deletions have been sequenced in three patients. Five patients had mitochondrial respiratory chain deficiency in complex I as shown by the low oxygen consumption in isolated mitochondria using three NAD(+)-linked substrates. Mitochondria with an abnormal ultrastructure were also observed in 2 cases. A good relationship between the cytochrome c oxidase deficiency and the amount of deleted mtDNA was shown in our present investigations.
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PMID:Deletions of mitochondrial DNA in Kearns-Sayre syndrome and ocular myopathies: genetic, biochemical and morphological studies. 185 20

A 9-year-old girl and an 11-year-old boy had ptosis, progressive external ophthalmoplegia, pigmentary retinopathy, and sensorineural hearing loss. The girl had diabetes mellitus and the boy had hypoparathyroidism. Both children also developed recurrent vomiting and cerebral infarcts with lactic acidosis. Muscle biopsy specimens showed ragged-red fibers and Southern analysis demonstrated a distinct heteroplasmic deletion of muscle mitochondrial DNA in each patient but no evidence of the point mutation in the transfer RNALeu(UUR) gene recently identified in mitochondrial encephalomyopathy, lactic acidosis, and stroke-like episodes (MELAS). These 2 children had combined features of Kearns-Sayre syndrome and MELAS, suggesting that mitochondrial DNA deletions occasionally can have pleomorphic clinical expression.
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PMID:Deletion of mitochondrial DNA in patients with combined features of Kearns-Sayre and MELAS syndromes. 189 71

Various mitochondrial DNA abnormalities have been described in patients with encephalomyopathies. We performed Southern blot analysis of skeletal muscle mitochondrial DNA in nine adult patients with clinical features and ragged red fibres suggesting mitochondrial dysfunction. Two patients with encephalomyopathy and two with the MERRF syndrome (myoclonus epilepsy with ragged red fibres) had the normal PvuII restriction pattern of muscle mitochondrial DNA. In contrast, mitochondrial DNA deletion was observed in two of six patients with ophthalmoplegia. One suffered from typical Kearns-Sayre syndrome and the other from isolated external ophthalmoplegia. None of these patients had affected relatives. The detection of mitochondrial DNA deletion in external ophthalmoplegia and their site and size support previously reported data.
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PMID:Muscle mitochondrial DNA in encephalomyopathy and ragged red fibres: a Southern blot analysis and literature review. 190 5

A 42-year-old woman was admitted for complaining of gait disturbance lasting for 2 years. She had a past history of hearing loss and bilateral ocular ptosis since her age of 21 years. Neurological examinations revealed severe external ophthalmoplegia, ptosis and muscular weakness of neck and extremities, but no dementia. Laboratory examinations showed high level of serum CK and slight elevations of CSF protein, lactate and pyruvate. The QT interval on ECG was prolonged. The EEG finding was slightly abnormal. The neurogenic pattern on EMG was noted. Muscle biopsy was performed at the quadriceps muscle. Its specimens demonstrated mixed changes of muscular atrophy and ragged red fibers. From these findings, Kearns-Sayre-Shy syndrome was diagnosed. It was noted in this case that brain MRI (T2-weighted image) revealed bilateral diffuse high signal intensity areas on cerebral white matter and brainstem. It seems that the lesions of central nervous system may progress subclinically for many years in cases of KSS, as our case shows.
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PMID:[A case of Kearns-Sayre-Shy syndrome with abnormal signal intensity on MRI in cerebral white matter and brainstem]. 193 67

Mitochondrial DNA (mtDNA) deletion is associated with a variety of clinical entities. In addition to progressive external ophthalmoplegia and Kearns-Sayre syndrome, mtDNA deletions have been demonstrated in Pearson's syndrome. We report an mtDNA deletion in an infant with a variant of Pearson's syndrome. Not only does she have congenital anemia, severe tubulopathy, and exocrine pancreas insufficiency, but she also has diabetes and cerebral atrophy. However, there are no signs of gut or liver involvement. Bone marrow improved while new tissues were involved, thus showing variability in progression of the disease. Decreased respiratory chain enzyme activities were demonstrated in muscle, and an mtDNA deletion was demonstrated in muscle, kidney, leukocytes, and fibroblasts.
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PMID:Congenital hypoplastic anemia, diabetes, and severe renal tubular dysfunction associated with a mitochondrial DNA deletion. 195 15

The various types of ophthalmoplegia described in the second half of the 19th century were attributed to degeneration of the oculomotor nuclei. In the middle of the 20th century, a reversal of opinions ascribed these disorders to a primary muscle lesion, and this was accepted as a dogma for 20 years. However, the finding of mitochondrial abnormalities, not only in muscles but also in the nervous system and in a variety of viscera, gradually led to the concept of a multiple system syndrome. Advances in biochemistry then revealed multiple alterations of the mitochondrial function, especially in the respiratory chain, and ultimately the concept of mitochondrial heredity was developed by molecular biology. At present, two approaches are possible. Those who opt for the first one consider that a large number of muscular, nervous, endocrine, cardiac, hepatic or renal abnormalities have as common substrate a disease of mitochondria producing unclassifiable biochemical abnormalities. Partisans of the second approach individualize, for clinical and genetic reasons, several autonomous syndromes, the best known of which is Kearns-Sayre syndrome. In any case, this evolution of concepts illustrates an advance in medicine: the starting point was a localized muscle lesion, while the end-point is a complex, multiple system dysfunction which, analyzed with increasingly greater precision, gives a glimpse of future therapeutic applications.
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PMID:[From muscle to central nervous system: birth and future of the mitochondrial encephalomyopathy concept]. 196 46


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